Can't wipe HD on old MacBook Pro

[Walter Sobchak]

I've just bought a new MBP Retina Display and want to wipe my old and rather tired MBP to give to a friend.
When I go into the boot up Disk Utility by holding the Command + R Key and click on earsing the hard drive, I get a warning come up which says unable to unmount drive/wipe drive and can't see any way around it.

The drive has been partitioned as I was using Boot Camp but I've already Wiped the Windows partition but it still exists.
Is there any way around this?, I just want to wipe the whole thing and put a fresh OS on it.

[marshalla]

Sounds like you can't wipe the drive it's launched Disk Utility from - which makes sense. Try a bootable USB stick with a Linux distro instead and use "dd".

[Stu R]

Sounds like you've got disk utility on the same partition.

Either pull the HDD and do it from another machine, Stick a bootable copy of Yosemite on an external (always handy to have lying around) or use target disk mode.

[Walter Sobchak]

Thanks for the advice, where would I get a Bootable version of OSX from?, I think I've still got the old CDs mine came with but that is Leopard or Snow Leopard.
Only thing I have is time machine backups on my external HD which isn't going to help as I don't want to restore the system.
I'd also like to revert it back to Mavericks if possible? as Yosimete ran really badly on it.

[Stu R]

Download Yosemite in the Mac App store, then choose one of these options (the second is how I do it)

http://arstechnica.com/apple/2014/10/how-to-make-y...

[Walter Sobchak]

I found my old Leopard Install CD and managed to boot it from that, seems to be working now.
The issue before was there is a very small partition OSX makes to boot from so I couldn't erase the HD.